A linear encoder (or simply an encoder) is a sensor, transducer or readhead paired with a scale that encodes position. The sensor reads the scale in order to convert the encoded position into an analog or digital signal, which can then be decoded into position by a digital readout (DRO) or motion controller.
A plotter is a computer printer that can be employed to print vector graphics. A plotter can be implemented as an inkjet plotter. An inkjet plotter can print by moving an inkjet nozzle (or an array of inkjet nozzles) or other instrument across a surface of a piece of paper. Inkjet plotters can draw complex line art, including text.